Histocompatible embryonic stem cells by parthenogenesis

Genetically matched pluripotent embryonic stem (ES) cells generated via nuclear transfer or parthenogenesis (pES cells) are a potential source of histocompatible cells and tissues for transplantation. After parthenogenetic activation of murine oocytes and interruption of meiosis I or II, we isolated and genotyped pES cells and characterized those that carried the full complement of major histocompatibility complex (MHC) antigens of the oocyte donor. Differentiated tissues from these pES cells engrafted in immunocompetent MHC-matched mouse recipients, demonstrating that selected pES cells can serve as a source of histocompatible tissues for transplantation.     

Characterization of cigar tobaccos by gas chromatographic/mass spectrometric analysis of nonvolatile organic acids: application to the authentication of Cuban cigars

A reliable method based on gas chromatographic/mass spectrometric (GC/MS) profiling of nonvolatile organic acids is described for the characterization of cigars. The method involves an aqueous extraction of ground tobacco and selective isolation of the acids by simply stirring strong anion exchange (SAX) disks in the aqueous tobacco extract. The acids are then directly silylated on the disk with N-methyl-N-trimethylsilyl-trifluroacetamide (MSTFA) in acetonitrile in an autosampler vial. Elution of the derivatized acids in situ allows the sample to be directly analyzed by GC/MS without further sample handling. Compared to the conventional disk-extraction technique using a vacuum manifold, this method is much less labor intensive, and is desirable for multiple sample analysis. Nicotinic acid, succinic acid, glyceric acid, malic acid, pyroglutamic acid, threonic acid, citric acid, uracil, and an unidentified acid were reproducibly quantified in tobacco samples. Principal component analysis (PCA) of the acid profiles of the filler tobaccos of 18 Cuban cigars and 31 non-Cuban cigars shows separation of the two groups, indicating that the acid profiles are potentially useful in the authentication of Cuban cigars.     

The dietary protein requirement of a bagrid catfish, Mystus nemurus (Cuvier & Valenciennes), determined using semipurified diets of varying protein level

Triplicate groups of Mystus nemurus (Cuvier & Valenciennes) were fed isoenergetic semipurified diets containing seven dietary protein levels from 200 to 500 g kg^–1 diet for 10 weeks. Dietary protein was supplied by graded amounts of a protein mixture (tuna muscle meal:casein:gelatine) at a fixed ratio of 50:37.5:12.5. Mystus nemurus fingerlings of initial weight 7.6 ± 0.2 g were fed close to apparent satiation at 2.5% of their body weight per day in two equal feedings. Growth performance and feed utilization efficiency increased linearly with dietary protein level from 202 to 410 g kg^–1 diet and declined with protein levels of 471 g kg^–1 diet or above. Protein efficiency ratio and apparent net protein utilization started to decline when the fish were fed with dietary protein levels exceeding 471 g kg^–1 diet. Fish fed with lower protein diets (202–295 g kg^–1 diet) had significantly ( P  < 0.05) higher carcass lipid content compared with fish fed with higher protein diets. Carcass lipid contents were inversely related to moisture content. Dietary protein did not significantly affect fish carcass protein and ash content. Using two-slope broken-line analysis, the dietary protein requirement for M. nemurus based on percentage weight gain was estimated to be 440 g kg^–1 diet with a protein to energy ratio of 20 mg protein kJ^–1 gross energy. This level of protein in the diet is recommended for maximum growth of M. nemurus fingerlings weighing between 7 and 18 g under the experimental conditions used in this study.     

The influence of a dietary lipid source on growth, muscle fatty acid composition and erythrocyte osmotic fragility of hybrid tilapia

An 8-week feeding trial was conducted to determine the effects of various dietary lipids on the growth, tissue proximate composition, muscle fatty acid composition and erythrocyte osmotic fragility of red hybrid tilapia, Oreochromis sp. Five isonitrogenous and isoenergetic semipurified diets were supplemented with 10% of either cod liver oil (CLO), sunflower oil (SFO), crude palm oil (CPO), crude palm kernel oil (CPKO), or a combination of 5% CLO with 5% palm fatty acid distillates (PFAD), respectively. There were no significant effects (P > 0.05) of diet on growth but fish fed the CLO diet showed a significantly (P< 0.05) poorer feed efficiency ratio compared to fish fed the CPO diet. Lipid deposition in fish muscle was mostly similar among fish fed the various diets but bone ash was significantly higher in fish fed the CPO and CPKO diets. Muscle lipids of fish fed palm oil-based diets did not increase in saturated fatty acids content but showed significantly lower polyunsaturated fatty acid (PUFA) concentrations compared to fish fed the CLO diet. The concentrations of individual PUFA in muscle lipids were strongly influenced by dietary PUFA concentrations. Dietary lipids did not markedly affect the structural integrity of erythrocyte membranes but the erythrocytes of tilapia fed the CPO diet were slightly more resistant to osmotic lysis. It was concluded that palm oil products, especially CPO, could be successfully used in the diet of hybrid tilapia based on its availability, cheaper costs and its potential ability to enhance oxidative stability due to its low PUFA content and high natural concentrations of antioxidants.     

Acute phase response in horses: changes in plasma cation concentrations after localised tissue injury

An acute phase reaction was elicited in four horses to which Freund's adjuvant was administered intramuscularly. The localised inflammation was accompanied by changes in the plasma concentrations of copper, iron and zinc. The plasma copper concentration, the plasma ceruloplasmin copper concentration and the ceruloplasmin oxidase activity in the plasma steadily increased to a maximum 24 days after the administration of the adjuvant. At this time, the plasma copper concentration was 2.2 micrograms/ml, a 90 per cent increase over the baseline concentration. The ratio of the concentration of plasma ceruloplasmin copper to plasma copper remained constant, indicating that the non-ceruloplasmin bound copper component of the plasma is also an acute phase reactant in the horse. The plasma zinc and iron concentrations decreased to 59 per cent and 30 per cent of their respective baseline concentrations and the severity of the inflammation appeared to influence the plasma concentrations of each metal. Weak correlations between the plasma fibrinogen concentration and the plasma copper and zinc concentrations of 25 horses with plasma fibrinogen concentrations of 5 g/litre or greater indicated that a single measurement of plasma copper concentration is not useful in the diagnosis of non-specific inflammatory disorders of the horse. However, the results suggest that the plasma copper concentrations in serial samples may be used to monitor the resolution of inflammatory disorders in the horse.     

Effect of palosein (superoxide dismutase) and catalase upon oxygen derived free radical induced degradation of equine synovial fluid

The effect of oxygen derived free radicals (ODFR) upon the specific viscosity of equine synovial fluid was studied. ODFR were generated either by a mixture of ferrous iron and EDTA (Fe/EDTA) or by a mixture of hypoxanthine and xanthine oxidase (HX/XO). Incubation of the synovial fluid with both free radical generating systems decreased its specific viscosity. When the synovial fluid was incubated with Fe/EDTA the specific viscosity of the synovial fluid was reduced rapidly. By 2 mins, it was 53 +/- 3 per cent of the original specific viscosity and by 30 mins it was reduced to 39 +/- 5 per cent. In the HX/XO system, the specific viscosity was 75 +/- 4 per cent of the original specific viscosity at 10 mins and by 50 mins it was reduced to 55 +/- 3 per cent. Palosein (superoxide dismutase) was an effective inhibitor of the free radical induced reduction of the viscosity of the synovial fluid when the free radicals were generated with HX/XO but not with Fe/EDTA. Catalase was moderately effective as an inhibitor of reduction in specific viscosity of the synovial fluid when the free radicals were generated by either system. Only minor synergy resulted when mixtures of Palosein and catalase were tested for inhibition of Fe/EDTA induced reduction in the specific viscosity of equine synovial fluid. The results indicate that Palosein may protect equine synovial fluid from the effects of the superoxide radical (O2-) but not from the hydroxyl radical (OH.).(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of pH and temperature on the hydrolysis of disodium acid pyrophosphate (SAPP) in potato processing

Disodium acid pyrophosphate (SAPP) is used in the potato industry for preventing after-cooking darkening of cooked and oil-blanched French-fried potato. SAPP-treated potatoes often develop a bitter off-flavor chemical taste due to large amounts of PO₄ absorbed from hydrolysis of SAPP solution. SAPP hydrolyzes directly to orthophosphate. Hydrolysis rate depends directly upon temperature and pH of the solution. The best control of after-cooking darkening is attained at pH 5 at 20–25°C. Increasing the concentration of SAPP solution has little effect on its stability at various temperatures and pH, and also made no great improvement on the color of the French-fry strips after par frying.     

Development and characterization of biodegradable films made from wheat gluten protein fractions

Gliadins and glutenins were extracted from commercial wheat gluten on the basis of their extractability in ethanol and used to produce film-forming solutions. Films cast using these gliadin- and glutenin-rich solutions were characterized. Glycerol was used as a plasticizer, and its effect on the films was also studied. Films obtained from the glutenin fraction presented higher tensile strength values and lower elongation at break and water vapor permeability values than gliadin films. Gliadin films disintegrated when immersed in water. The GAB isotherm model was used to describe the equilibrium moisture sorption of the films. The glycerol concentration largely modified mechanical and water vapor barrier properties of both film types.     

Double-dip caustic peeling of potatoes I: Laboratory-scale development

A modified caustic peeling process for potatoes was developed and evaluated. The process, called the double-dip process, comprises two separate caustic applications with an intervening holding period. Results on Russet Burbank potatoes showed that tissue removal was enhanced for the double-dip process when compared to the standard single dip process and that the double-dip process can effect reduction in caustic usage without requiring additional heat input.